LPP’s Newly Assembled DPF Achieves First Shots and Pinch

The baby is born! After seven years of theoretical work and raising money, five months of design, five months of construction and assembly, and a week of testing, LPP now has a functioning dense plasma focus, Focus-Fusion-1. The first shot, using helium as the fill gas, was achieved at 5:29 PM today, Oct.15, and the first pinch was achieved at 6:04 PM on the second shot. The fact that a pinch was achieved so soon was evidence of the soundness of the design.

The following is taken from LPP’s announcement:

First Shots Fired

[Refresher: What was the goal of the first shots?]
The shots were produced with a charging potential of 20 kV, a bit less than half the full bank charge of 45 kV. We will not know the exact current achieved until we reduce some instrumental noise in the next day or so. It is probably around 0.9 MA and within 10% of our predictions.

The pinch is clearly evident in the voltage probe curve, below, of the sixth shot. The first peak is when the machine turns on, while the second, higher, peak in voltage is from the energy transfer into the pinch region and the plasmoid.

Machine Assembly

LPP’s team completed assembly of the Focus-Fusion -1 Dense Plasma Focus at 12:30 AM Oct.10. We were racing the clock to complete assembly while John Thompson, who led this phase, was still in NJ. Dr. Thompson had to return to San Diego on Oct.10. We began initial testing of the device up until 5:30 AM on the 11th when we ran out of time (and energy!). We succeeded in evacuating the vacuum system to 1.5 millitorr, (two millionths of atmospheric pressure) and in charging the capacitor bank repeatedly to 25 kV. However, we were unable to get the trigger system, which triggers the 12 switches on the capacitors, to function, so we did not yet have our first shot. We worked to resolve the issue this week and are very pleased by this day’s results.

Next Steps

The first shots represent the first in a series of shots that will be taken along the road to demonstrate the scientific feasibility of Focus Fusion as a net source of clean, abundant, cheap energy. The machine is still in the initial phase of fine tuning and “conditioning”. In addition, we need to locate a leak in the vacuum system in order to pump down to our goal of a few microtorrs before re-filling with deuterium. Finally, we still need to put in place all our instruments, several of which must also be assembled. We hope to complete all this shortly and be ready to start data collection.

Thanks to…

LPP is especially indebted to Dr. Thompson for the outstanding work he has done in the detailed design of FF-1 and in his unflappable leadership and very long hours of hard work in constructing the device over the past six weeks. LPP President Eric Lerner and Senior Research Scientists Murali Subramanian and Abdelmoula Haboub also actively participated in this work. We were assisted by Joe Gorman of Frank Construction. Rezwan Razani, Executive Director of the Focus Fusion Society, also pitched in when needed, as well as recording our effort in stills and video (see the Focus Fusion website). Thanks to all!

Congratulations and bravo on your first shot and first pinch. An earlier post had suggested that the device would require about 20 shots of “conditioning” before the insulator would be able to sustain a pinch. Is there anything about the design of your insulator which would explain the rapid conditioning process, whereby pinch was achieved 10 times sooner than expected?

That’s interesting, Rezwan. What actually happened in the misfires? Did the plasma torus fail to form, or did any charge actually reach the cathodes at all? I’d kind of assumed that there was some kind of disconnect between the capacitors and the electrodes so that nothing happened with them at all (in which case no conditioning could have occurred.)

Suggestions on finding vacuum leaks, I always start at the pump and dead head it with a gauge to be sure it pumps to spec vacuum. After that I would take a squirt bottle of alcohol and apply alcohol to suspected areas of were a leak might be, this is usually a 2 person operation, what you will see is a dip in the pressure momentarily and then a rise back up to were it is stable.
You can use water but that takes FOREVER to pump out of a vacuum system. If you do not find the leak squirting alcohol you can start disconnecting anything that you can put a cap on like were the gas comes in, it could be leaking from the inside, or the vent valve. If none of that works you will need a helium leak detector. I hope this helps find your leak.